DESCRIPTION: This application requests support for a study to determine the psychometric properties of a new measure of trust/mistrust of the medical care system. The Medical Mistrust Index Version 2.1 (MMIv2.1) was initially developed to test the hypothesis that mistrust is a determinant of under-utilization of medical care services among racial minorities and as such will help explain race disparities in utilization of healthcare services. However, we believe that the concept of trust/mistrust has much broader implications for health services research. Development of the measure has been ongoing since 1996. In a pilot study using a small "convenience sample" the MMIv2.1 has displayed promising psychometric properties. We now seek support to conduct a study to validate the measure and establish its psychometric properties in a community sample. There are two specific aims: 1. To establish the reliability of the Medical Mistrust Index Version 2.1 2. To establish the validity of the Medical Mistrust Index Version 2.1